Automatic limit stop



Oct. 9, 1928.

W. C. SWANCOTT AUTOMATIC LIMIT STOP Filed Aug; 12, 1927 fie'tnessesjnuemr:

h'ffl TEE C Swan c077 and are adapted to be Patented Get. 9, 1928.

' WALTER c. swnncor'r, on CLEVELAND, onto.

I AUTOMATIC LIMIT STOP.

Application filed August 12, 1927. Serial No. 212,522. i

This'invention relates to motor limit stops and, while not limitedthereto, relates more particularly to "a limit stop for crane motors andthe like, and has for its object theprovision of a novel'stopconstruction which will be entirely free from all springs, weights,contact points and similar parts which ordinarily wear and break or failto function when only slightly worn.

Another object is to provide a stop mechanism which is purelymechanical, and one in which the action is positive even though.

the parts be considerably worn.

In the drawings- Figure 1 is a diagrammatic plan View showing 'myinvention applied toa crane operating mechanism. 1 v

Figure 2 is an end elevation thereof.

Referring more particularly to the drawings, the numeral 2 designatesthe cable drum ofa crane which has its shaft 3 journaled in suitablebearings l and 5. One end of the shaft 3 is extended and connectedthrough a train of gearing 6 with a drive shaft 7, which shaft isconnected by a coupling 8 with the power shaft of a motor 9, which maybe of any desired form, but is shown as an air or fluid motor.

A controlling mechanism of any desired standard construction isindicated by the numeral 12 and is provided to control the operation ofthe motor 9. The control mechanism 12 is adapted to be operated by areciting lever 13 secured on a shaft 14-. The lever 13 is provided withoperating cables 15 which are secured to its opposite ends pulled torock the lever 13 to provide for manual control of the motor. p

A stop shaft 16 having a square portion '7 and a threaded portion 18 ismounted above the motor 9 and control lever 13. The squared portion ablymounted in a bearing 20, and the threaded portion 18 of the shaft 16 hasa threaded engagement with a nut 21 which nut 15 jourualed in bearings22 and 23 and provided with a hub portion 24: adapted to bear againstand deliver end thrust to'the bearings. I

A sprocket 25 is secured on the hub portion 24: of drive chain 26 to asprocket 27 secured on the drum shaft 3, so that the nut 21 will berotated when the drum 2 is rotated. Rotation of the nut 21, due to itsfixed mounting justably secured on lever 31.

over the shaft 16 intermediate the 17 of the shaft 16 is slid-- the nutand is connected by a in the. bearings'22 and engagement with the shaft16, will cause the shaft 16 to move longitudinally through the nut. i Apair of 'stop'collars 28 and 29 are adlilte, and are-adapted to engage arocking Thelever 31 has'its lower end shaped to form a cle'vice 32 whichis fitted stop collars 28 and. 29 and has its upper end secured to a rocshaft 33' journaled in bearings 34:.

Tillie shaft 33 also has a lever 35' secured thereto' and positionedsubstantially at right angles to the lever 31; The lever 35 has itsother end connected to the upper end of a vertically disposed lever orlink 36' which has its lower end pivotally connected to" one end of therocking lever 13 of'thecontrol mechanism 12. i

In operation, the stop collars 28 and 29 will be adjusted on the shaft16 so as to be in position to engage and rock the lever 31 when thedesired amount of travel is im-.

drum 2, which drum is directly parted to the When the limit connected tothe nut 21.

23, and its threaded the shaft 16 at spaced 7 points by means of setscrews 30or the of travel is reached in either direction, one

of the collars 28 or 29 will engage the lever 31 and rock the lever 31and shaft 33 which in turn will move the lever 35 and link 36 andthereby rock the control lever 13 into horizontal or off position so asto operate the control mechanism 12 and stop the motor 9 and drum 2.

lVhile I have shown and described one specific embodiment of myinvention, it will be understood that I do not wish to be limitedthereto, since various modifications may be made and the invention maybe applied to many other apparatuses than cranes without departing fromthe scope of my in vention as defined in the appended claims.

I claim 1. The combination with a motor and a control element for saidmotor, of means being vadapted to compel ,a longitudinal movement ofsaid screw shaft, stop elements on said shaft, and means operated bysaid stop elements adapted to operatesaid motor control element to movesaid element into off position.

2. The combination with a motor and a control element for said ,motor,of means operated by said motor for automatically operating said controlelement, said means ,oomp-rising a screw shaft mounted for longitudinalreoiprooatory movement and locked against rotary movement, a nut havingthreaded engagement with said shaft, said nut being flour-na led infixed bearings, drive means oonneeting said nut with said anotor wherebysaid nut will be rotated when said motor ispperated, the rota-tionofsaid nut being ad p ed to cflmpel a longitudinal movemen-tof saidsorewshaft, stop collars adjustably mounted ;at ,spaced points on said shaft,and leve me hanism a apted t be engag d and operated by said collarswhen said shaft is reoiprooated, said lever mechanismbeing ,eonnectedwith and adapted :to operate said motor ,controlelement to move saidelement into fi m men- The s m nwtiqn wi a motor and a control elementfor said otor, of means motor is operated, the rotation of'said nutbeing adapted to compel a longitudinal movement of said screw shaft,stop collars adj ustably shaft, a lever having a fixed fulcrum pointrelative to said screw shaft, a clev-is on one end of said lever andfitted over said :shaft intermediate said stop collars .so as to beengaged byt-saidstop {collars when said shaft is caused to movelongitudinally by the rotation of said nut, said lever being adapted tobe rocked about its {fulcrum point when said clevis is engaged by saidstop collars, and other levers operated by said first named lever ,andadapted to operate said motorcon trol element to move said element into{off position.

mounted at spaced points on said I In witness whereof, I have hereuntosigned my name.

WALTER swanoorr.

